<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
</head>
<body>


<script>

    class person {
        constructor(props) {
            super(props);

        }

        de () {
            return 4
        }

        aa (){
            alert(1)
        }

        bb(){
            this.de = 5
        }
    }

    let b = new person();

    console.log(b.de());

</script>
</body>
</html>
